Unlocking VMware With a Storage Virtual Appliance - SvSAN Demonstration

www.stormagic.com/Webinars/webinar_2012_04_04.php

Description

VMware® users need a flexible, robust and cost effective shared storage solution for their virtual server environments. Shared storage systems are required in order to leverage the real benefits of vSphere (such as VMware HA, VMotion TM and DRS TM), but are often seen as out of reach, too complicated or expensive for many organizations.

Prior to the development of Storage Virtual Appliances, customers needed expensive and complex external SAN solutions to enable high-value features such as VMware HA, VMotion and Dynamic Resource Scheduler (DRS). This server based storage typically costs a fraction of what an external SAN costs and is much easier to manage.

As part of the webinar we demonstrate fast deployment and creation of shared storage, ease of use through vCenter integration as well as high availability. As part of the discussion we also highlight the benefits of Storage Virtual Appliances and why SvSAN is a favorite in SMB and multi-site environments


Q&A

Please note that some frames of this recording have been edited/removed to help focus on key elements of the demonstration. high availability demonstration took approximately 60 seconds for fail-over to complete.

Q:What jumbo frame settings are supported by svsan? 1500 or 9000 only, or is there an infinite number of frame settings that can be set depending on your nics/switches?

A: Frame settings are fully customizable and can be set to any MTU length.


Q: Can HyperV be used as host?

A: Although HyperV and XenServer cannot run SvSAN it can access SvSAN iSCSI targets. SvSAN simply presents iSCSI targets which can be accessed by any iSCSI initiator. You could create a SvSAN Mirror host on VMware and present it to a HyperV host.


Q: Has 24x7 support been initiated?

A: This is currently being finalized and we plan to have 24/7 support in effect by the end of the month.


Q: Are backup capabilities also built into the product?

A: There are currently no backup features in SvSAN but are on our current roadmap starting with Asynchronous replication of SvSAN Mirrored datastores.


Q: What is the minimum VMWare license required to allow VM Failover with SvSAN?

A: You can achieve VM Failover with any version of VMware ESXi. The VMware HA feature is only included in Essentials Plus but the SvSAN can control VM failover on lower version of VMware i.e. Essentials. VM failover is configured through the SvSAN interface and controlled by the SVA's themselves.


Q: How do you prevent split brain from occuring?

A: To ensure data integrity it is essential that both SVAs participating in a mirror have the same view of the mirror state. If, for any reason, each SVA were to run independently the mirror could enter a 'split-brain' situation, where each side of the mirror had a different view of the state of the mirror. This could occur if the network connection between the two sides of the mirror was lost. It could also occur is side A of the mirror was shut down while side B continued, then side B was shut down after which side A was started. In this case side A would have no way of knowing what happened to side B while side A was shut down.

To prevent split-brain situations occurring SvSAN supports the use of a Neutral Storage Service (also called a quorum or tie-breaker service), running on a third, physically independent host. This is the only way of reliably preventing a split-brain situation occurring, but it does require a third physically independent host.

If a third physical host is not available it is still possible to run mirroring, but there are certain situations which could result in split brain occurring, with potential data loss. Fortunately it is possible to minimize the risk of this occurring through careful system design.


Q: Any recommendations on the Cache configuration for a three or more node cluster?

A: A: The SVSAN currently supports 2-way mirroring although it is possible to split mirrors across multiple hosts. These can either be presented as individual datastores, three in the case of a three node cluster, or VMware extents could be leverage to amalgamate the three targets. VMware extents do not use stripping so there maybe performance impacts. Caching should be performed by the RAID controller with a BBU.


Q: Does SVA have the ability to store writes in a journal so random IO can be turned into serial?

A: No


Q: Does SvSAN support Infiniband?

A: No


Q: Do you leverage the underlying VMFS dirty block list to optimize mirroring?

A: SvSAN is iSCSI and operates on block level below VMFS. It has no interaction with the above file system


Q: Are there any snapshot capabilities built in?

A: No


Q: Any VM tuning to maximize performance for SVA guests?

A: If you follow the Deployment Guide the SvSAN should be at optimal performance. You may wish to change the VMware Path Policy under the SW iSCSI adapter to use Fixed or Round Robin. Our support team will be more than happy to review environments and make individual recommendations.


Q: Can performance be improved through para-virtualization?

A: We recommend using the Paravirtual SCSI Controller for the SVA VM. To achieve the best performance:

More Disks/Spindles = better performance

Disk Speed i.e. SATA vs SAS vs Solid State

Storage Allocation Technique, RDMs and VMDirectPath offer the best and similar performance

RAID Controller Cache


Q: What components work the best in a server to make the highest performance StorMagic dual node configuration?

A: The biggest performance factors for the SVA are:

More Disks/Spindles = better performance

Disk Speed i.e. SATA vs SAS vs Solid State

Storage Allocation Technique, RDMs and VMDirectPath offer the best and similar performance

RAID Controller Cache

You should Reserve 2GHz and 1GB RAM for each SVA


Q: I thought HA broke the auto power-on policy. Do your have something special setup for the SVA?

A: This was dependent on the SVA being powered on when the Host was hard rebooted. If an SVA is powered off before reboot it will not power back on. It is possible to script powering on VMware VM which would include an SVA. This can be triggered at boot time to ensure the SVAs come up.


Q: Does your SvSAN Server auto power on after reboot?

A: This was dependent on the SVA being powered on when the Host was hard rebooted. If an SVA is powered off before reboot it will not power back on. It is possible to script powering on VMware VM which would include an SVA. This can be triggered at boot time to ensure the SVAs come up.


Q: For the NSH, what does that do to the target machine? Any ports or permissions need to be open to enable it between the NSH and the SVAs?

A: The NSH is normally installed onto the vCenter machine by default and simply runs as a background service. As mentioned, it can be installed to another Windows Server OS as a single service.

NSHService Port : 23569


Q: Performance - what is the best IOPS that StorMagic has seen for SvSAN? Can you describe the basic configuration (disk rpm, raid, # of spindles).

A: Performance document will be supplied upon request. It will also include how the tests were run so comparison figures can be generated.


Q: Why can't you add the RDM from the VM settings interface? Add disk - rdm - local lun.

A: RDMs were traditionally used by VMware to map iSCSI and FC targets directly to VMs. VMware has now enabled users to map internal drives/arrays as RDMs but the option needs to be enabled in the ESXi Host Advanced Settings profile. We have found with older servers it does not always work but is still possible via the CommandLine.


Q: If I rebuild my environment, and I'm adding back my licensed SVAs, do I add any license key, or is it specific to the host?

A: Licenses are unique and require a reset request when re-installing.


Q: Can you use 1 vCenter server as the NSH for multiple locations / clusters?

A: A single NSH can be used for over 1000 SVAs.


Q: Can you use 1 vcenter server as the NSH for multiple locations / clusters? or do you need an NSH in each location

A: A single NSH can be used for over 1000 SVAs.

Author: Anonymous

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